Vitamin D plays an important role in the health of older adults, especially bone health. “One of its most important jobs is helping us absorb calcium, which makes it essential for maintaining strong bones and preventing conditions such as osteoporosis,” said Johannah Katz, RD, a registered dietitian in Orlando, Florida.¹ 

Vitamin D is different from most other vitamins. While you can get it from food and supplements, your body can also make it when exposed to sunlight. Vitamin D acts like a hormone in the body, says Samantha Snashall, RDN, a registered dietitian nutritionist at The Ohio State University Wexner Medical Center in Columbus, Ohio. 

“Keep in mind, as we age the ability of our skin to make vitamin D declines,” she said. “Additionally, people with darker skin tend to make less vitamin D due to the amount of melanin. Using sunscreen also affects vitamin D production.” 

There are two kinds of vitamin D: D2 and D3. Vitamin D2 comes mainly from plant sources and fortified foods. Vitamin D3 is found in animal foods and is the kind our bodies make when exposed to the sun’s UV rays. 

What does vitamin D help with?

Vitamin D is best known for helping the body absorb calcium. This helps keep bones strong and can help protect older adults from osteoporosis. Vitamin D also supports normal muscle, nerve, and immune function. It may also help control inflammation. Recent research on the benefits of vitamin D for older adults have linked it with better brain health and mood and a lower risk of dementia.^{3, 4} More research is needed to show whether vitamin D itself prevents these problems.

Vitamin D2 and vitamin D3 both help support bone strength and immune function. But they are processed differently by the body.² D3 tends to be more efficient at raising overall vitamin D levels in the blood.

Vitamin D also:

• Supports normal muscle function
• Helps the immune system work properly
• Supports nerve function
• Helps the body use calcium and phosphorus
• May help control inflammation

Some emerging research has linked vitamin D with improved mood, cognitive function, and lower risk of some chronic diseases.^3,4,5

Some early research even found that supplementing with vitamin D could help slow aging at the cellular level.⁵ Again, further research is needed to support these findings. And this does not mean everyone should take extra vitamin D. 

“Whether someone actually needs a supplement, and at what dose, should take their overall diet, medical history, medications, and clinical situation into account,” Katz said. 

Individuals that may want to consider and talk to their provider about supplementation include older adults, people with conditions like Crohn’s disease, ulcerative colitis, celiac disease, and cystic fibrosis. Additionally, individuals that are considered obese and or have a history of bariatric surgery may want to consider supplementation."

– Samantha Snashall, registered dietitian

How much vitamin D should a 65-year-old take?

For a healthy 65-year-old, the recommended daily amount of vitamin D is 600 international units (IUs) or 15 micrograms (mcg). This is the recommended daily amount for adults ages 19–70. The recommended dosage of vitamin D for seniors over 70 is 800 IU (20 mcg) per day.¹

“Low vitamin D levels aren’t uncommon,” Katz said. There is some debate about the optimal amount of this vitamin in the blood. But roughly one in four American adults have vitamin D blood levels that are too low or inadequate for bone and overall health, according to the National Institutes of Health.¹

Some groups are more likely to have low levels of vitamin D:

• Older adults
• People with limited sun exposure
• People with darker skin 
• People with a condition that impairs fat absorption (vitamin D is a fat-soluble vitamin)
• People with higher weight or a history of gastric bypass surgery

That does not mean everyone in the above groups needs a high-dose supplement. “The 2024 Endocrine Society guideline recommends against routine vitamin D testing or routinely taking doses above the RDA in otherwise healthy adults ages 50–74,” Katz said.⁶ But she recommends discussing it with your health care provider. This is especially important if someone has risk factors for low vitamin D or symptoms that suggest a deficiency. “That can help determine whether they actually need a higher therapeutic dose rather than guessing with supplementation,” she said.    

Can you take vitamin D with other medications?

Vitamin D supplements are generally considered safe. But they can interact with certain medications. For example, some weight loss medications, such as orlistat, affect how much fat your body absorbs. Vitamin D is a fat-soluble vitamin. This means it needs to be in the presence of fat to be digested. A medicine like orlistat that blocks fat absorption may reduce how much vitamin D you actually get. Similarly, some anti-inflammatory drugs called corticosteroids can lower vitamin D levels. And certain diuretics prescribed for high blood pressure may raise calcium levels too high. 

Be sure to consult your health care provider about vitamin D supplements. Mention any other medications or supplements you may take. 

If you receive the green light from your provider [to introduce a vitamin D supplement], you will want to make sure the supplement you choose has been third-party tested. This means the supplement has gone through testing to ensure it has exactly what the label says it has in it. Supplements are not FDA-regulated, meaning they can add harmful contaminants like heavy metals without the customer knowing. If it is third party tested there will generally be a badge or stamp saying this or that it is 'verified' on the container somewhere."

– Samantha Snashall, registered dietitian

What are the symptoms of vitamin D deficiency in adults?

Vitamin D deficiency does not always cause clear symptoms, especially when it is mild. This can make it hard to know if you are getting enough vitamin D. When levels get very low, however, problems with your bones and muscles may develop. “More significant deficiency can lead to bone pain and muscle weakness, and severe deficiency can cause osteomalacia, in which bones become soft and weak,” Katz said.

Here are some of the possible symptoms:

• Bone pain
• Muscle weakness
• Bone fractures
• Muscle aches or cramps
• Trouble walking or climbing stairs

What are the side effects of too much vitamin D?

It is also possible to get too much vitamin D. “This tends to be rare unless you are taking a hefty dose of supplementation in addition to having vitamin D foods,” Snashall said. Like other fat-soluble vitamins, vitamin D can accumulate in fat tissue and the liver and reach toxic levels. But it is nearly impossible to reach those levels through routine sun exposure or food alone. 

“More is definitely not always better,” Katz said. “Excessive supplemental vitamin D can cause calcium levels to become too high. Severe toxicity can cause kidney failure or abnormal heart rhythms.” Most adults should not exceed 4,000 IU (100 mcg) per day. If you are considering a supplement, ask your health care provider what dose is right for you.

Here are some of the excess vitamin D risks for seniors:

• Nausea and vomiting
• Weakness
• Confusion
• Loss of appetite
• Excessive thirst and urination
• Kidney stones

What foods have vitamin D?

There are not a lot of foods that naturally contain vitamin D. Fatty fish like salmon are among the best natural sources. “Thankfully, a lot of the foods that are common in the average American diet like dairy and breakfast cereal are already fortified with vitamin D,” Snashall said. Fortified foods have vitamin D and other nutrients added to them. “It's generally not too hard to get enough unless you have a dietary restriction to those foods or dislike them,” she said.  

Here are some other foods that contain vitamin D:

• Salmon
• Trout
• Tuna
• Mackerel
• Beef liver
• Egg yolks
• Cheese
• Vitamin D-fortified milk
• Vitamin D-fortified plant milks
• Fortified cereals
• Fortified yogurt
• Fortified orange juice

Mushrooms can also be a source of vitamin D. Like your body, mushrooms manufacture vitamin D when exposed to sunlight. Many varieties you buy at the store are exposed to UV light for this reason. You can also cut mushrooms and place them in a sunny spot for at least 15 minutes to boost their vitamin D levels at home.⁷ 

How to get more vitamin D-rich foods into your diet 

Adding more vitamin D-rich foods to your meals does not have to be difficult. You can try eating salmon or trout a few times per week. You can also choose vitamin D-fortified foods like milk (or plant-based milk), orange juice, cereal, and yogurt, Katz says. “I always recommend checking the Nutrition Facts label because vitamin D fortification varies considerably between products,” she said.

In one residential care facility, adding UV-treated mushrooms to one meal a day for four weeks increased the vitamin D levels of residents by 180 percent compared to those who got the standard (non-mushroom) menu.⁸ Mushrooms tend to be low in calories, so this can be a simple way to get more vitamin D in your diet. 

When eating more vitamin D-rich foods, make sure you are eating them in a meal that contains some fat, she noted. “Vitamin D is a fat-soluble vitamin, so taking it with a meal containing some fat may also improve absorption.” In one study of older adults, vitamin D levels were 32% higher in those who took vitamin D supplements with a meal containing fat compared to those who took it with a fat-free meal.⁹

The American Academy of Dermatology recommends obtaining adequate vitamin D through food and supplementation when needed rather than increasing UV exposure because UV radiation increases skin-cancer risk."

– Johannah Katz, registered dietitian

Frequently asked questions 

How much vitamin D should I take per day?

For healthy adults ages 19 to 70, the recommended amount is 600 IU (15 mcg) per day. Adults 71 and older need 800 IU (20 mcg). The correct vitamin D for seniors dosage may be different for those with a deficiency or certain health conditions.

Do you need more vitamin D as you get older?

Yes. The recommended amount increases from 600 IU per day for adults up to age 70 to 800 IU per day for adults 71 and older.

What is considered a normal vitamin D level for older adults?

There is no single agreed-upon blood level that defines the perfect amount of vitamin D for older adults. Your health care provider can offer guidance on what is healthy for you personally.

What is the difference between vitamin D2 and vitamin D3?

Vitamin D2 comes mainly from plant sources and fortified foods. Vitamin D3 is found in animal foods and is also made by the skin when exposed to sunlight. 

Questions? Email us at reviewsteam@ncoa.org.